Ahh - this really sounds like you are making this harder than it should be. I like to have the following kind of structure (below). In the XP fashion I like to write my tests first as I build up the object. I must admit to not using h2xs that much, but we have a template that is used to create new modules which need to inherit from a base class anyways so I guess we're still being structured (whew).

project/lib/Foo/Bar/Baz.pm
project/lib/Foo.pm
project/t/test1.t

$ cat t/test1.t

use lib './lib';
use strict;
my $error;
BEGIN { 
  use vars qw($TESTCOUNT);
  use Test;
   # so we actually do some more stuff
   # here to load the Test module
   # since we distribute it with our package
   # in case the user doesn't have it

  $TESTCOUNT = 3;
  plan tests => $TESTCOUNT;

  # do some other testing
  eval { Some::module::Needed; };
  if( $@ ) { $error =1 }
}

END { 
   # if we exit prematurely in the test the testcount
   # will still be okay (assuming we want to bail
   # when some module isn't installed or 
   # or the network is unavailable, etc.
  foreach ( $Test::ntest..$TESTCOUN) { 
    skip("unable to run all the tests",1); 
  }
}      

if( $error ) { exit(0) }

use Foo;
use Foo::Bar::Baz;

my $foo = new Foo(-id => '10');
ok($foo);
ok($foo->id, '10);

my $baz = new Foo::Bar::Baz(-magicword => 'peanutbuttersandwiches');
ok($base->magic, 'peanutbuttersandwiches');

$ perl -I. -w t/test1.t
1..3
ok 1
ok 2
ok 3
[download]

The above wasn't actually run but hopefully I didn't leave any typos in - if you don't want to put things in a lib directory you can always s/lib/ above and all will work (your would be doing use lib '.' instead). You can also have PERL5LIB set to include XXX/project/lib. I may be overzealous using the perl -I. -w for my tests when I have PERL5LIB set, but since often I have version of the toolkit installed while I'm working on the next one, I don't want to get confused about which code I am actually running.